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starting problems
12-31-2013, 05:55 PM (This post was last modified: 12-31-2013 06:03 PM by bigbuck.)
Post: #1
starting problems
I have a 2001 sc1 with a 1.9l engine with 230000 mi here in the heart of Packer country. The car starts fine when it is cold. After running it a few minutes, and turning it off, it will not restart unless I push the peddle to the floor while turning it over. When it is running it seems to run fine. I have replaced the spark plugs and cleaned the throttle body. I pulled the plugs since trying those few things and find them to be all carboned up. I also checked the fuel pump and that seems to be working fine. It idles at 1000 rpms even at operating temperature which I think is a little high. Could I have a throttle position sensor going bad or an idle control valve? Any help is greatly appreciated. Thanks.
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12-31-2013, 10:40 PM
Post: #2
RE: starting problems
I would start with a scan for live data, which means finding someone with a full function scanner who knows how to use it and is also familiar with Saturn's quirks. You will likely find a temp sensor that is out of range or something similar.

You mentioned cleaning the throttle body, but it's the IAC (Idle Air Control) on the side of the throttle body that sets the speed. Remove the intake boot again and look for a small hole right next to the butterfly. Squirt the cleaner into that opening several times and try again. This will not clean the plugs but may get the idle to calm down. (it's something you should do anyway) I suspect the real issue is the ECM thinks the engine is cold so it's telling the IAC to hold the speed up and keeping the mix rich. (black plugs) This would also account for your hard starting and having to hold the pedal down to clear it out.

Let us know how you make out.
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01-16-2014, 03:42 PM
Post: #3
RE: starting problems
A quick question... Will the temperature sending unit, sending a bad signal, tell the car it is running too cold and cause these problems. The thermostat is only about 15000 mi old and the car heats up, but the temp gauge does not get too high on the dial. I replaced the coil pack/icm with one from the bone yard and I'm still idleing at around 1100 rpm when warmed up. Thanks for all your help. Eric
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01-16-2014, 04:56 PM
Post: #4
RE: starting problems
The simple answer to your question is, "No." The theory of what you are asking is, "Yes." Here's why. The "Temperature sending unit sends information to the dash gauge. It usually just has one wire going to it that supplies a ground to the gauge. The "ECT Sensor;" Engine Coolant Temperature Sensor, sends information to the computer which can tell the car it's running too cold. This sensor usually has two or more wires going to it.

Understanding how the system works can help you understand why Rupe said to use a Full Function scanner to see what is going on. You can spend a lot of money throwing parts at it hoping to get the right thing or use a scanner and get the right part the first time. The scanner can show you exactly what temperature the computer is seeing along with a multitude of other things.

I am also curious as to what you mean by, "The car heats up." How hot does it get? How long has it been doing this? The reason that I ask is that it is really common to get air trapped in the system after replacing a thermostat. If the air pocket is near the ECT it can cause faulty readings. Those faulty readings can cause the problems you are having along with fans not running at the proper time.

All of that leads to the question of, "Is the Check Engine light on?" If it is there may also be codes stored that could point you in the right direction.

Fill in those blanks for us and we can provide better advise.

Thanks for using the forum,
Garner

Interested in Mining? Look here: Coal Mining, PA
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01-17-2014, 12:15 AM
Post: #5
RE: starting problems
To clarify further....

As Garner mentioned there's more than one temp sensor.

There's the sensor that tells the dash gauge what to do, which has no bearing on what the ECM sees. This is strictly for the driver's info. (if it's ok)

There's also sensor for the ambient air temp and yet another for the coolant temp and both of these are what the computer sees to make it's adjustments to the fuel mix. This is where the scanner comes in handy. If it says the air is 30 degrees and you know it's 90 outside there's a problem. If it says the coolant is 30 degrees and the radiator hoses are too hot to touch, there's another problem. You see where this is going?

OK, obviously if you can't put a hand on one of the hoses because it's too hot then the dash gauge should read more than 160 degrees and possibly closer to 190. (normal) This is the point where most people can only touch a hose for maybe 2 seconds. 120 - 140 most people can take for 5-10 seconds at least. This is just to give you an idea of how hot things are. This is not actual temp but feeling the outside of the hose by hand.... and watch out for moving parts when doing this sort of thing.
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02-04-2014, 11:03 AM
Post: #6
RE: starting problems
Problem solved! I removed the coolant temperature sensor and found it to have a crack in it. After replacing it, many problems disappeared. Starting and idle returned to normal, the coolant low light went out on the dash, and the transmission shifts normally again. It is amazing to me how everything is so interconnected. Along the way I have learned many things. Thanks for all your help. Now it is on to replacing the control arms. UGH! it never ends.
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02-04-2014, 11:15 AM
Post: #7
RE: starting problems
Thanks for getting back to us with that info. I'm sure someone else reading here will appreciate it when they run into a similar issue.

Control arms..... dirty grunt work but a necessary evil to a functioning vehicle!
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